Relay valve



Aug. 4, 1936. s. voREcH ET Al. 2,049,984

.I RELAY VALVE l Filed-Aug. 24, i951 2 sheets-sheet 1 EG Z u INVENToR.

STEP/fw VaPEc/f WLF/PED A EAM/v A ORNEY.

Aug. 4, 1936. s. voREcH ET AL.v u 2,049,984

RELAY VALVE Filed Aug. 24, 1931' 2 sheetssheet 2 A TTORNE Y.

Patented Aug. 4, 1936 UNlTEo STATES PATENT oFFiCE RELAY VALVEApplication August 24, 1931, Serial No. 558,974

1l Claims. (Cl. 303-26) This invention relates in general to automotiveair brake systems and in particular tothe control valves for trailerbrake equipment.

i the various valves employed to control the operation of the trailerbrake equipment the socalled application and release valve and theemerlgency valve are of most importance, and it is with a view toincreasing the eillciency of these valves that the present invention visdesigned. The former valve functions to apply-and release the trailerbrakes and the latter serves to automatically apply the brakes in caseof a break in two between the tractor and trailer.

It is a particular object of the invention to pact structure, which isin contradistinction to the conventional practice of making thevalvesseparate and distinct units. Such a structure effects an economyof manufacture by virtue of the a elimination of parts, and likewiseincreases the eiiectiveness of the valvular control, the few partstending to minimize the possibility of inoperativeness.

Inv one desirable arrangement a single valve stem within the combinedvalve assembly serves as a common mounting for both the inlet valve andthe automatically operated closure valve of the emergency valvestructure.

A further feature of the invention relates to certain details of thelemergency valve wherein opposed springs act on the valve operatingdiaphragm to render the same less sensitive to pressure differentials,obviate leakage and in general insure a more uniform operation of thediaphragm. v

rA. still further object of the invention resides in means for obviatingundesirable blowing down" oi the reservoir pressure due to a rapidopening and closing or oscillatory movement of the intake valve. Thisvibratory or oscillatory effect is de, among other causes, to theinertia of the parts.

Further features of the invention including the provision oi anemergency valve unit detachable from the application and release unit,novel details oi' construction and combinations of parts will becomeapparent from the detailed description oi the invention to follow, takenin conjunction A with the raccompanying drawings illustrating theinvention. in which:

Figure l is a. diagrammatic view of truck and trailer brake equipmentembodying one form of our combinedrelay and emergency valve;

Figures 2 and 3 are sectional views through the body oi the combinedvalve of Figure 1;.

combine the aforementioned valves as one com- Figure 4 is a sectionalview through a modiiled form of application and emergency valvestructure. l

Referring in general to the brake system in which the aforementionedvalve assembly is incorporated, there is disclosed diagrammatically inFigure 1 truck and trailer brake equipment comprising a tractorreservoir lll charged by compressor l2 with the usual governor i4 andair gage i6 in circuit. Master valve i8, of the self- 10 lapping type,located on the truck controls the brake pressure of the front and reartruck brake chambers 20 and 22 respectively, and also controls, througha service line 24, the operation of our combined relay and emergencyvalve 26, the 15 latter controlling the operation of the trailer brakechambers 28. The air pressure for the trailer chambers is supplied by atrailer reservoir 30, the pressure of the latter being maintained bythetruck reservoir through the intermediary .of the control valve as willbe explained in greater detail hereinafter.

Our invention is particularly concerned with the refinement of thetrailer control valve structure. As disclosed in Figures 2 and. 3, avalve body 32 is closed at its ends by caps 34 and 36. The cap or cover34 serves to compress spring 38 against washer 40, the latter sealingthe periphery of a rubber valve operating diaphragm 42 against a ringflange 44 in the body of the valve. The 30 diaphragm t2 is attached tothe stem t6 of a. piston-like guide member 48, the latter being normallyspaced a predetermined distance from a.

-stop 50 integral with the valve bodythe said member 48 constituting aguiding spider having 35 spaced peripheral portions 49, arms 5i andspaced peripheral ports 5I. The diaphragm 42 normally rests upon asecond flange 52 on the valve body and also upon the peripheral edgeiiange 54 on the guide. The flanges 44 and 52 integral 40 with the valvebody together outline the exhaust port of the valve opening toatmosphere at ports 56, Figure 3.

The diaphragm and attached guide serve to actuate valve stem 58, the endof the latter hav- 45 ing a sliding iit within a bore in the guide. Thestem serves as a mounting for intake valve 62, which is normally pressedagainst its seat 64 by compression spring 66, the latter beinginterposed between an emergency valve operating diaphragm 50 68 and theend cap 36. Diaphragm 68 is sealed at its edge against the cap 36 bycompression spring l0. Spring 66is particularly useful in maintaining a.tight seal of the intake valve 62 upon its seat, thereby obviatingleakage at this 55 I point; this spring also makes the valve less sensi-'the seating of the diaphragm upon the cap and compensates for anywarping of the diaphragm which might result in leakage. Inasmuch as theemergency action of the valve structure is dependent upon a tight sealat this point, the function of the spring in maintaining the seal isthus apparent. emergency valve member 16, the rubber seating member 18of which is adapted to seat at 88.

In operation, a slight opening of the master valve I8 serves to admitair under pressure to thev truck brake chambers `28 and 22 throughconduits I9 and 2| respectively to thereby actuate the truck brakes. Aportion of this air serves to operate the trailer valve 26 approximatelysimultaneously with the operation of the truck brakes. In this valveoperation air under pressure is admitted through conduit 24 to chamber82 above the diaphragm 42, forcing thelatter with its attached guidedownwardly to open intake valve 82, placing the trailer brake chambers28 in communication with the trailer reservoir 38 via conduit 28, valvechambers 14 and 12, and conduit 8|. It is to be particularly n'oted,however, that the emergenc'y valve 16 is not closed during thisoperation, this being obviated by the contact of the guide with stop 58,and that accordingly air under pressure from chamber 12 passes intochamber 84 past open valve 16.

If the master valve actuating member is momentarily held in openposition, the degree of air pressure to the truck brake chambers and tothe trailer control valve is limited to a predetermined maximum, this byvirtue of the well-known lapping of the master va1ve. When the pressurewithin the chamber 84 in the trailer control valve increases to a degreesuch that the opposing forces on the diaphragm 42 balance each other,the intake valve 62 closes without, however, venting the chamber 12 toatmosphere, the valve control being then balanced or lapped and' thetrailer brakes held applied. This lapping of the valve is substantiallycoincident with the lapping of the master valve, any lag due to air now,etc., bein substantially negligible.

Upon further applicationof the master valve the aforementioned cycle isrepeated, and upon release of said valve by venting the same thereduction of pressure in chamber 82 creates a pressure differentialbetween chambers 82 and 84 suillcient to permit upward movement of theguide and the venting ofthe trailer brake chambers to atmosphere viaports 5|* and 86, see Figs. 2-4.

The air removed from the trailer reservoir during the aforementionedbrake application is replaced from the truck reservoir, the air beingconducted by emergency line 86 to chamber 88 entering at port 88 andthence flowing around the edge of diaphragm 68 into chamber 14 and intothe trailer reservoir. The spring 18 is suillciently weak to permit thenecessary yielding of the diaphragm. The pressure within chambers 14 and88 is, therefore, at all times approximately equal, which renders thediaphragm 88 normally ineffective to disturb intake valve 82.

Referring. now to the emergency operating phase of the valve structure,if the trailer should accidently vbreak away from the truck, severingthe air hose connections 24 and 86, there would automatically result arapid reduction in pressure in chamber 88, communicating with hoseconnection 86.. The air in chamber 14 under trailer The valve stem 88also supports an.

sealed at 4 the emergency valve ||8 is held 'I' reservoir pressure thenpresses the diaphragm 88 downwardly at its edge to seal thecommunication between chambers 14 and 88, the pressure diiferential alsoserving to move the central por.- tion of the diaphragm downwardly toseat the 5 valve 18 and open inlet valve 82. The trailer brakes are thusautomatically applied by air under pressure from the trailer reservoir88 through pipe 28, chamber 14, past open inlet valve `82. chamber 12,pipe 8|, to `the brake chambers 28 tp l0 decelerate the disconnectedtrailer and bring the safme to an emergency stop.

A very compact valve assembly is thus provided, the valve stem 88serving as a common mounting for the emergency valve 18 and the inletvalve 8h15 the latter being automatically opened-during the emergencyphase of the valve operation. It will also be noted that-by removingspring 18, diaphragm 68 and the valve 18 there remains a ooml pletelyoperable application and release valve 20 assembly which may function assuch without the aid of the collateral emergency assembly Provided bythe aforementioned parts. l l

'There is disclosed in Figure 4 an embodiment of relay and emergencyvalve structure wherein the 25 units are to a degree separate, beingsecured together by pads 88 and 82 on the respective units. The relay orapplication 'and release valve unit comprises a rubber diaphragm 84serving as an exhaust valve in the manner heretofore described 39 withrespect to the valve of Figures 3 and 4,.and more particularly describedin our copending application No. 509,857, illed January 19, 1931.

Chamber 86 is connected to .the master valve a through anyintake pipeconnection, not shown, 3 and the chamber 88 below the diaphragm isadapted to be connected to the trailer brake chambers. through' normallyopen valve ||8 and ducts |28 and |2|.

The diaphragm 84 is normally in such position as to maintain the brakechambers vented to atmosphere via duct |28, chamber 88 guiding spider|22 having ports 8|* and exhaust chamber 88. When air is admitted tochamber 88 by the master valve, the diaphragm 84 is deil'ected 45inwardly to close the exhaust valve constituted by the diaphragm and rim81 and open an inlet valve |88, thus permitting air to now from thetrailer reservoir through a suitable pipe connection to chamber |82 andpast inlet valve |88 into chamber 88 and thence to the brake chambers.The inlet valve |88 closes 4when the pressure in chamber 88 builds upsubstantially equal to that created in chamber 88. When the service linepressure is exhausted by thel master valve, the diaphragm 84 isdeflected upwardly by the pressure in chamber 88 the full amount torelease airY from the trailer brake' chambers.

The emergency valve unit, also disclosed in Figure 4 and secured asabove described to the 60 relay unit. contains a similar diaphragm |88having an emergency valve ||8 attached to it. 'Ehe chamber I2 isconnected to the emergency line, and this pressure holds the diaphragmsealed at ||4, and air under pressure passes around the edge of thediaphragm charging the trailer reservoir via intercommunicating cham-lbers I|8 and |82 and passage |82* connected with said reservoir. Withthe diaphragm thus away trom its seat allowing the passage of air fromchamber |84 in the relay valve to chamberV ..||8 in the emergency valveand hence to the .brake chambers viaduct |28 in the emergency valve andports therein, not shown.

v Cn

Should the trailer break away from the tractor, or the hose burst, thesudden reduction thus brought about in the emergency line will lower thepressure acting on diaphragm |08 so that .trailer reservoir pressure inchamber 6 acting downwardly upon the diaphragm will move it breaking theseal at Ill, resulting in an upward ilow of air around the emergencyvalve stem to the brake chambers, thusv producing an emergencyapplication of the trailer brakes. It will l be noted that with thisoperation the valve ||0 is closed by the downward movement of thediaphragm, thus cutting off the brake chambers from chambers ||8 and|04, which are at this time open to atmosphere. This action also causesa sealing of the diaphragm |08 at its edge upon its seat closing theopening to the emergency line, so that the brakes are held appliedwithout leakage through the ruptured lines.

A particular feature of the above described embodiment lies in thedetachable mounting of the emergency valve unit to the application andrelease or relay valve unit. Either unit may 4thus be employed to theexclusion of the other by merely connecting the trailer reservoir andAbrake chambers to the respective ports 'at the securing pads. y

A further feature of the invention relates to of the intake valve. Thisundesirable action occurs when the pressure in chamber 96, Figure 4, vissuddenly dropped from a high pressure to nearly atmospheric and then assuddenly raised, say to about twenty pounds. This operation of themaster valve is often made necessary during quick complete release andimmediate reappli- ,cation of the brakes. With this particularoperation, the diaphragm 94 and connected inlet Valve |00 arethrown'into a state of continuous os'cillation, the energy to sustainthis` oscillatory eiect being derived from the compressed air of thetrailer reservoir.

Explaining this unusual action, the .sudden reduction in pressure abovethe diaphragm causes an appreciable pressure differential forcing thediaphragm rapidly upward. Due to the large area of the`exhaust Valve,the pressure in the lower chamber Sii!4 drops below that of the upperchamber 96 before the exhaust valve can close. This pressure diierentialcauses the diaphragm and guide to move downwardly again at high speed,the valve operating guide |22 striking a hammer blow on the intake valvestem |24 downwardly suiciently to again open the intake valve. There isthus incurred a condition of continuous oscillation sustained by theenergy of the air entering the intake valve and resulting in a leakagefrom the exhaust port, which will rapidly blow down the reservoir. rIfhefrequency of the vibration is, among other variables, a function of thediaphragm diameter, diaphragm stiffness, weight of the reciprocatingparts, tension of the intake valve spring, volume of the various airchambers and the size of the various ports. y

In order that this undesirable effect be obviated, there is suggestedthe provision of friction means in the form of a spring brass ring |26installed in a groove in the spaced peripheral portions 49 of theguiding spider |22 and adapted to press against the wall of the guidebore with a slight tension, thus imposing va slight friction impedingthe motion of the guide. This structure is entirely successful, thefriction imposed on the guide being suicient to retard its motion andthrow it out of phase with the natural vibratory period of the system,the vibration or oscillatory effect being immediatelyv dampened out.

There is thus provided a very compact trailer brake control structure,the relay and emergency valves functioning to quickly and effectivelyapply and release the brakes under all conditions of service. A

It will be understood that while the illustrated embodiments of the,.invention are described as shown, a considerable latitude is to bepermitted in construction within the-range of the appended claims.

We claim:

1. A valv'e assembly for fluid pressure brakes comprising, incombination with a brake chamber and a reservoir, a casing member, avalve stem mounted for reciprocatory movement in said casing, inlet andemergency valve members mounted om said stem, and means in said casingconstructed and arranged to actuate said thereby place the reservoir incircuit with the brake chamber to energize the latter andvapply thebrakes.

3. A valve assembly for uid'pressure brake comprising, in combinationwith a brake charnber and a reservoir, a casing member, a valve sternmounted for reciprocatory movement in said casing, inlet and emergencyvalve members mounted on said stem, a diaphragm operated guide memberhaving a telescoping slide lit with said stem and adapted to actuate thelatter to open said inlet valve without however closing vsaid emergencyvalve member to thereby place the `reservoir in circuit with the brakechamber to energize the latter and apply the brakes.

4. A valve assembly for uid pressure brakes mounted on a tractor drawntrailer comprising, in combination with a brake chamber and a reservoir,a casing member, a valve stem mounted for reciprocatory movement in saidcasing, inlet and emergency valve members mounted on said stem, means insaid casing constructed and arranged to actuate said stem to open saidinlet valve without however closing said emergency valve member tothereby place the reservoir in circuit with the brake chamber toenergize the nuid pressure brakes ranged to actuate said stem to opensaid inlet valve without however closing said emergency valve member tothereby place the reservoir in circuit with the brake chamber toenergize the latter and apply the brakes and a flexible diaphragm alsomounted'on said stem for automatically opening said inlet valve toeffect an emergency application oi the trailer brakes in the event oi abreak in two between the tractor and trailer. a

6. A valve assembly for iluid pressure brakes comprising a casing,-avalve stem within said casing mounted'for reciprocatory movement, inletand emergency valve members mounted on said stem and oppositely disposedvalve oper ating ilexiblediaphragms within said casing', each of saiddiaphragmsvadapted to impart movement to said valve `stem inv onedirection.

7. A valve assembly for a tractor. and trailer iiuid pressure brakingsystem comprising, in combination with a brakev chamber, a traileri'eservoir, a tractor reservoir and iiuid transmitting connectionsextending from said chamber and reservoirs, a valve housing means havinga pair of open ends, closure members at each o! said .open ends,partitions within said housing means, a` pair o! independently movableparallel valve members mounted for reciprocatory movement in saidhousing means, and a valve operating diaphragm at each of said ends ofsaid housing means, one oi said diaphragme having its peripheral portionresiliently urged into contact with a portion of said housing means, theintermediate portion of said diaphragm cooperating with said housingmeans toform an exhaust valve, said diaphragms, partitions and closuremembers together deilning iluid receiving chambers, said housingmeansand at least one oi' said closure members being provided with ports tointerconnect said chambersand -the aforementioned iluid transmittingconnections.

8. A valvevassembly tor a tractor and trailer iluid pressure brakesystem comprising, in coml bination with -a brake chamber, a trailerreservoir, a tractor reservoir and iluid transmitting connectionsextending from said chamber and reservoirs, a valve housing means havinga pair said housing means, and a exible valve operating diaphragm ateach o! said ends oi said housing means, one ofsaid diaphragms havingits peripheral portion resiliently urged into contact with a portion oi'one of said closure members, said peripheral portion constituting withsaid last named closure member an intake valve iorsaid trailerreservoir. said dia, partitions and closure members together definingfluid receiving chambers, said housing means and at least one ot saidclosure members being provided with ports to interconnect said chambersand the aforementioned iluid transmitting connections.

9. In a valve assembly for the purpose da seribed,va valve body, aclosure member secured toone end of said body, a valve stem within saidvalve body mounted for reciprocatory movement. a valve member mounted onsaid stem, a diaphragm member also mounted on said stem. said diaphragmmember denning, together with said body member and closure member, twoiiuid receiving chambers, yieldable means interposed between the endwall ot said valve body member and said diaphragm and other yieldablemeans interposed between the diaphragm and said closure member.

1Q. In a fluid pressure braking system having a brake chamber, a valvedevice including a caswith said brake chamber, a reciprocatory intakevalve having an annular valve seat in said casing for controlling thepassage of iluid under pressure into said casing chamber, resilientmeans valve, means controlled by movement oi' said diaphragm in anotherdirection upon release of fluid pressure from said diaphragm forexhausting iluid from said casing chamber, and means :or automaticallydampening vibration oi' said intake valve set up during operationthereof comprising a resilient ring carried by said guide member andfrictionally engaging the wall of said casing chamber.

11. A valve assembly for iluid pressure brakes comprising a casing, aclosure member for said casing, a valve stem in said casing mounted forreciprocatory movement therein and having a valve head thereon, adiaphragm carried by said stem and denning with said closure member andcasing two iluid receiving chambers, a spring interposed between saidcasing and the peripheral portion of said diaphragm and normallymaintaining said portion in contact with said closure member, and asecond spring interposed between said closure member and diaphragm.

STEPHEN VORECH. WILFRED A. EATON.

l ing-having a chamber therein communicating 3

